Meters for making electrical measurements by contacting points to be measured with measurement probes are well-known. An example of such a known meter is a digital multimeter. Conventionally these meters indicate the measured value on either an analog or a digital visual display while the measurement probes are in contact with the points to be measured. The user is therefore required to view the display to read the measured value while maintaining the measurement probes in contact with the points to be measured, which can be difficult in some cases.
This difficulty can be exacerbated by the size and/or arrangement of circuit components and surrounding materials. For example, in recent years, the electronics industry has tended toward high-density electronic circuits. In such circuits the electrical parts and connections are physically mounted close together to reduce the overall size of the circuit. These high density circuits often require electrical testing by measuring the voltages, currents or resistances of various points in the circuit with a meter to verify proper operation. The physically small size of the parts requires test personnel to accurately manipulate the meter's measurement probes to make contact with portions of the circuit. This manipulation is often difficult even if the operator has a clear and unobstructed view of the meter probes and the measurement point at the time when contact is made.
U.S. Pat. No. 6,433,530, issued on Aug. 13, 2002 describes a hand held, i.e. pen type circuit and polarity tester, the disclosure of which is incorporated by reference in its entirety. Where a definition or use of a term in a reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies herein and the definition of that term in the reference does not apply. Pen type probes generally include one or more contact leads that are attached to various locations of an electrical circuit or ground, and a probe that is easily manipulated with a single hand of a user to contact a measurement point. A light, such as an LED, or a buzzer indicates one or more characteristics of the measurement point.
In some applications, it is desirable for the probe to indicate more detailed information about the measurement point. FIG. 1 illustrates an example of a known probe device with a digital display; item EECT400, available from Snap-On USA, which includes an LCD that displays a measurement voltage, and green and red LEDs that respectively indicate operative ground and power connections. However, in many cases, testing a measurement point requires moving the probe to a position that results in the portion having the LEDs and/or voltage display being obstructed or not visible to the user.
U.S. Pat. No. 4,864,226, issued Sep. 5, 1989, describes a multimeter that includes a meter which includes a voice synthesizer, and a measurement probe that includes a voice output switch. When a user presses the voice output switch, the voice synthesizer converts a measurement into a voice signal. This enables a user to manipulate the probe with one hand and use the voice output button to take measurements when the probe or meter is out of view. However, the meter is not optimized for the testing of high-density electronic circuits. In an example, the body of the meter can prevent the probe from reaching a measurement point. In another example, there may not be a surface available upon which to rest the meter, requiring a second hand of the user.
Therefore, what is needed is a circuit testing device that can output detailed information about a measurement point without requiring a separate meter body, so as to enable a user manipulate the device with a single hand.